Asian Silver Carp: A Clear and Present Danger

Perhaps nothing has alarmed the fishing public as much as the Asian silver carp invasion of rivers and lakes in the U.S. There are primarily three reasons for this alarm.

One, no sure-fire method has been developed/deployed that will stop the silver carp from infiltrating connected lakes; Two, the non-native fish presents a boating hazard to occupants of a craft on the water; And three, the potential for decimating game fish in an infested body of water. This article attempts to shed a little more light on this “plague” and specific information regarding the silver carp invasion in north Alabama lakes, namely, Pickwick, Wilson, Wheeler, and Guntersville.

Asian carp photo courtesy of TWRA.

According to TVA, Asian carp were first introduced to public waterways in the early 1990s when they escaped from aquaculture ponds in the delta areas of the Mississippi River during extreme flooding. Since then they have migrated through the Missouri River and the lock-and-dam systems of the Ohio, Tennessee and Cumberland rivers according to TVA River Neighbors publication.

TVA says three of four invasive species of Asian carp—bighead carp, silver carp, and black carp— are relatively new to the system and pose the biggest threat. Grass carp—also known as white amur—are the fourth species and are commonly used as a biological control for aquatic nuisance plant species. Grass carp pose little threat to the Valley’s waterways in comparison to the three other species. The silver carp is the species most concerning to boaters’ safety.

“We want boaters to be aware that these fish jump,” Frank Fiss, Tennessee Wildlife Resources Agency (TWRA) Chief of Fisheries explains, “It is not like the fish target you, but people should be wary of their random jumps. Anyone hit by large carp could be injured.”

Wikipedia also notes the silver carp’s jumping ability. “Silver carp have become notorious for being easily frightened by boats and personal watercraft, which cause them to leap high into the air. The fish can jump up to 8–10 ft. into the air, and numerous boaters have been severely injured by collisions with the fish.

Note the low placement of the silver carp’s eyes. This is a good identifier for the fish. USGS gov photo

According to the EPA, “reported injuries [from jumping carp] include cuts from fins, black eyes, broken bones, back injuries, and concussions.” Silver carp can grow to 99 lbs. in mass. This behavior has sometimes also been attributed to the very similar bighead carp, but this is uncommon. Bighead carp do not normally jump when frightened.

Catching jumping carp in nets has become part of the Redneck Fishing Tournament, in Bath, Illinois. Other parties, such as the Peoria Carp Hunters, have taken advantage of the jumping ability as a mechanism of hunting the carp, in some cases to purge the invasive species.

To further reduce the possibility of these occurrences, TWRA recently partnered with the Kentucky Department of Fish and Wildlife Resources to host a tournament. During the 12-hour event, 81 teams harvested 17,000 pounds of Asian carp.

Courtesy Phil D. Ekema.

Although these nuisance carp cannot swim into all reservoirs, they could be unintentionally introduced by a fisherman. Fiss said, “Small carp look very similar to threadfin shad and gizzard shad, and we don’t want anyone to mistake them and accidentally move them to new waters.” When the fish takes residence in a body of water the population may grow very quickly since a spawning silver carp carries over a million eggs. The numbers are incredible even though just a third of the eggs survive.

INVASION UNDERWAY IN THE TENNESSEE RIVER
A recent article by Robert Montgomery in the BASSMASTER B.A.S.S. Times publication included a story about the silver carp in Kentucky Lake.
Montgomery wrote about a May 2018 Elite tournament on Kentucky Lake saying, “But what professional anglers saw on Kentucky Lake and Lake Barkley was real: millions of silver carp milling about in waters they had wanted to fish.”

Montgomery also wrote about what Elite angler Mark Menendez saw during the event. “Carp were grouped up in the back of major creeks with little current. Giant schools of silvers, 15-to 25 pounders, were scattered in there.” Menendez noted “ [the silvers] were taking ambush locations with current, where bass used to be. They were making lots of noise and chasing gamefish away.”

1.The first question for Ekema was for an update on the amount/degree of any infestation in each of the lakes.
Ekema said, “Currently we do not have a real good idea of the density of the silver carp invasion. We know that Pickwick’s population of silver carp is expanding and currently has the highest population of all the Tennessee River reservoirs in north Alabama. He continued with this invasion breakdown that indicates Pickwick has a clear and present danger:

Wilson Reservoir
No confirmed reports of silver carp. Fish must be in Wilson or traveling through Wilson to get to Wheeler.

Wheeler Reservoir
2015: Two positive eDNA samples from Guntersville Dam tailrace.
2017: One confirmed silver carp captured by a commercial angler.
2017 – 2018: Quite a few unconfirmed angler reports of silver carp with the majority of them coming from the Flint Creek area near Decatur, AL.

Guntersville Reservoir
No reports of silver carp.

Ekema added, “Angler reports of silver carp have increased but so far are limited to Pickwick and Wheeler Reservoirs.”

2. Our second question regarded the status of plans to stop the spread.
Ekema replied that stopping the spread is impossible unless you shut down the navigational locks and that isn’t going to happen. Our best hope is to deter or slow down the spread. The installation of a sound barrier may be our best hope of deterring these fish from migrating upstream. An experimental sound barrier is to be installed below Lake Barkley in the near future. If it works then we propose a barrier to be installed below Guntersville Dam. The price of a barrier will be well over one million dollars. No current funding is available.

3. Next, the question was, Are there any current systems/devices deployed to stop the spread upstream?
Ekema noted that there were NONE in Alabama.

4. What about any new systems/devices being developed to stop the spread upstream?
Sound, light, and bubble barriers have been used individually or in combination. Sound barriers appear to show promise.

5. Any estimated timeline of the spread, if any, into all the lakes?
That has probably already happened. Our hope is that they will not successfully spawn. However, silver carp have successfully spawned in the lower Tennessee and Cumberland rivers.

6. What actions could fishermen take to assist Fisheries in the effort to stop/reduce the invasion?
Small silver carp look very similar to native fish species such as skipjack herring, gizzard shad, and threadfin shad. Live bait anglers that capture their own bait with cast nets could unknowingly capture silver carp and transfer them to other water bodies.
DO NOT transport bait fish to other bodies of water but instead “Use ‘em only where you catch ‘em”.

Take several pictures if possible, especially of their ventral (belly/chest) area and the gill filaments.

7. What is your best guess of the impact on recreational fishing in these lakes if the spread is not stopped?
There is potential for silver carp to overwhelm the river system and to out-compete native species such as gizzard shad, threadfin shad, and larval game fishes for plankton. Plankton is an essential food source for most, if not all sport fishes (bream, crappie, bass, stripe, sauger) in their larval life stage, and, to all filter feeding fish such as shad (gizzard and threadfin), paddlefish, mussels, and snails.

Well, there you have it anglers. The picture painted is not very good- certainly “A Clear and Present Danger.”

About Southern Fishing News

Our center of publication and local coverage is the north Alabama region. Our online news carries on the tradition of Southern Fishing dating back to the late 1970's with the Southern Fishing Television Show, then the print publication Southern Fishing.